Rocket Massless Heater?

Posts: 3

posted 7 years ago

So i've been looking into the rocket mass heater. I live in a 1500sq/ft home on a slab. It is a modern open floor plan style. Not only is the house not designed for wood heat, but we have a 2yr old and another on the way.

I'm having a hard time figuring out how a mass heater could fit into our home to heat it properly.

Could i just build the same structure without the 'mass' and blow all the heat off the exhaust tubes for a traditional radiant heater? I've seen several suggestions to just use a typical wood stove however i don't understand why. If the rocket heater is more efficient, and i could recover more heat from the exhaust it still seems like a better solution than a traditional heater.

Posts: 31

posted 7 years ago

I am no expert on this but have been following alot on this subject. The mass is what gives its efficiency. Air in its self has no way to hold the heat like a mass would. So with out the mass, I would think you would be better off with a wood stove. Some of the things that come up are, if the air in your house was 50 degreesF, A rocket stove burning wood with mass around it may be over 100 (or somewhere close), so being near it or sitting on a bench would make you feel plenty warm with out burning constant wood source. As far as putting one in your house, you do have to realize unless I am missing something here, that your insurance agent probably will not like you. I would like to build a micro house someday in my backyard, then build a rocket stove in it. Probably did not answer your question for you!

enuro12 wrote: So i've been looking into the rocket mass heater. I live in a 1500sq/ft home on a slab. It is a modern open floor plan style. Not only is the house not designed for wood heat, but we have a 2yr old and another on the way.

I'm having a hard time figuring out how a mass heater could fit into our home to heat it properly.

Could i just build the same structure without the 'mass' and blow all the heat off the exhaust tubes for a traditional radiant heater?

No, don't do that. The mass heater is much safer for your little ones. A traditional wood stove (or mass-less rocket for that matter) would likely have a surface temperature of over 400 degrees... instant burn on touching. A mass heater is designed for a surface that is safe to touch even at it's hottest. If it is hotter than that it has been "over-fired". I don't know about the RMH, but the traditional masonry heaters have been test fired to 3x over-fire (means 3x the normal wood load) without failing (they tear the heater down after to check the inside condition). The RMH relies on a very small firebox and longer feed time so that by the time it could be over fired it already feels quite warm in the room, giving the negative feed back to the operator to stop feeding more wood in. The RMH does have one hot spot to watch for at the top of the barrel where the bare metal is exposed.

Anyone I know of that has a conventional wood stove and children has put a fence around it.

I'm with Len on this one. Not only does the mass store heat without danger to the occupants, it also covers all the pipes and seals any minor defects in the metal work which reduces the chances of CO2 or carbon monoxide leaks.

Posts: 19

posted 7 years ago

i have a 3 y.o. and a 7 m.o. the older has never been stupid around fire. he was warned early and often about heat. i suspect your children have an innate fear of pain, as well. you may not need to worry about he kids in your planning. they'll figure it out probably easier than anyone.

sounds like being on a slab allows for maximal benefit from the cob/masonry mass.

I've been looking at building one for a while also. I like the idea of pushing hot air under the house. The heater would be in an outside BBQ area so it would heat 2 places at the same time. I was going to use a funnel over the fire so i can set up a grain or wood pellet feed.

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